I agree that the opportunity cost is higher for older founders, but (as others have observed) so is the probability of success, at least vs. non-YC younger founders. It's also true that, if you are willing to live like a grad student, you can mitigate your risk by doing consulting/contract work beforehand or on the side. So could a 23-year-old, of course, but for a variety of reasons they usually don't bill at nearly as high a rate. I don't have to work very long at $100-125/hr. before I've got a year's living expenses saved up.
The real catch is if you have a family to support. I'm (un)lucky enough not to have that problem.
I started my current company when I was 26. I think back to that time (1999) and I didn't blink an eye when it came to the risk. I jumped in quickly, without worrying about it.
Now its 8 years later. I have a wife, a kid, a house payment, etc. I would definitely think a lot harder about making that type of move now. Obviously, my salary is higher (which is one aspect of it), but the big reason is that my obligations are much higher. If I miscalculated now, my family would suffer greatly.
So in general - I'd say younger people with less obligations and responsibilities, are more able to take that type of risk.
Also, a company may be formed by tech people who get laid off and motivated out of necessity. What is the risk for them in this case?
http://en.wikipedia.org/wiki/Expected_value
I'm only pointing it out because I also want to note that it's a great way to determine if the contestants on Deal or No Deal are being boneheads.... ;-)
First "market value". All other things being equal, someone who has a typical salary of 300k has a lot more opportunity to save for a couple of years of no salary and will find it easier to come back to a decent salary if the startup fails than someone who only makes 20k.
However, all other things are not equal. The relevant factor is overhead. Overhead is associated with age but isn't determined by age. For example, young folks supporting other folks have exactly the same problem as older folks supporting other folks.
Note that overhead is typically the result of choices and comes with benefits. Those with less overhead typically made different choices and don't get the benefits. Also, "young founders" are often delaying overhead.
Note that overhead contributes little/nothing to a startup's odds of success.
BTW - One could argue that the market actually undervalues not-yet-known-to-be-successful 22 year old founders.
For young folks, there's little risk and opportunity cost but with zero experience likelihood of success is small.
For older folks, there's more risk and opportunity cost but with more experience and connections likelihood of success is greater.
This isn't a penal system, this is a distribution system. Being young isn't the prerequisite to success. Everyone harps and focuses on it because of that trait is unique (remember, likelihood is small) in an otherwise older folks dominated field (remember, likelihood is bigger).
This only applies if you have optimized your career around being an employee, though. Someone who makes $300K/year obviously has, and has picked up quite a few skills on being productive and navigating office politics. But a 50-year-old homeless bum who just got his life back together faces the same incentives as the 22-year-old startup founder - perhaps even moreso, because employers will look at a gap in work experience with suspicion.
And it seems like many of the businesses started by older founders fit this pattern - either they've just been fired and lost everything, or they're housewives returning to the workforce, or they're senior citizens looking for a career change. Once you've got nothing to lose, you've got everything to gain.
But maybe you are referring to early startup employees? I can see what you say being the case in that type of situation, where salary is typically low in exchange for more equity.
But I'm not speaking from experience either.
Very often not the case.